1. Field of the Invention
The present invention relates to an aliphatic polyester stretched film, an aliphatic polyester composition which is a raw material of the stretched film, and a package using the stretched film. More particularly, the present invention relates to an aliphatic polyester stretched film which has degradability within a natural environment, has excellent flexibility and heat resistance and manifests no bleeding of a plasticizer, an aliphatic polyester composition which is a raw material of the stretched film, and a package using the stretched film.
2. Related Art of the Invention
Recently, treatment of plastic wastes have been featured. Plastic molded articles such as packing materials have been disposed by burning, land reclamation and the like after use thereof. However, when plastic wastes are burned, high combustion heat leads to a durability problem with the incinerator. Substances such as polyvinyl chloride sometimes generate harmful gases causing environmental pollution. Further, in the case of the land reclamation treatment, plastic molded products are not completely degraded and remain semi-permanent in original form, causing problems of influence on the natural environment.
Due to such conditions, various biodegradable plastics which are degraded completely by microorganisms within the natural environment and are degraded into natural by-products, carbonic acid gases, water and the like have been invented, and are used at a practical level. For example, Japanese Laid-Open Patent No. Hei-6-340753 discloses a resin composition mainly comprising polylactic acid which is an aliphatic polyester, or a lactic acid-other hydroxycarboxylic acid copolymer. It has been disclosed that this resin composition, for example, can be used as a raw material of a degradable card (sheet), and this card has a high mechanical strength and manifests practical durability, and the like. However, this resin composition has a high elastic modulus and rigidity, and poor flexibility. Therefore, this resin composition is not suitable for use that requires flexibility in which polyethylene, polypropylene, soft polyvinyl chloride and the like are generally used.
In general, there are known, as methods for softening a resin, (1) addition of a plasticizer, (2) copolymerization, (3) blend of a soft polymer, and the like. Among them, investigations for softening using various plasticizers have been made, as in method (1). For example, Japanese Laid-Open Patent No. Hei-4-335060 discloses a composition obtained by adding a plasticizer to polylactic acid. As specific plasticizers, diisobutyl adipate, dioctyl sebacate and the like are listed. However, these have a low plasticizing effect, and sufficient flexibility is not obtained. Further, when these plasticizers are used, bleeding of a plasticizer occurs directly after molding or over time causing variation in flexibility, transparency and the like.
Method (3) is limited to a method adopting a biodegradable resin having flexibility as a blend resin, if biodegradability is taken into consideration. Regarding a biodegradable resin having flexibility, for example, JP-A Nos. 8-245866 and 9-111107 disclose polybutylene succinate, polyethylene succinate, polycaprolactone and the like. However, for imparting sufficient flexibility (tensile modulus of 1.0 GPa or less) to lactic acid-based polymers, it is necessary that the above-described biodegradable resin is added in large amounts (for example, in the case of polybutylene succinate, 60 wt % or more). Consequently, heat resistance, transparency and the like which are characteristics of lactic acid-based polymers deteriorate.
The object of the present invention is, in view of the above-described problems, to provide an aliphatic polyester stretched film which has excellent flexibility, heat resistance and transparency and manifests no bleeding of a plasticizer, an aliphatic polyester composition which is a raw material of the stretched film, and a package using the stretched film.
The present inventors have carried out an intensive study to solve the above-described problems, and as a result, have found that an aliphatic polyester composition can be obtained which manifests suppressed bleeding of a plasticizer and is suitable as a raw material of molded products such as a film and the like having excellent transparency, heat resistance and flexibility, by selectively adding a specific plasticizer to an aliphatic polyester. Also, it has been found that an aliphatic polyester stretched film having flexibility can be obtained without decreasing transparency and heat resistance of the film due to bleeding of a plasticizer, by film-molding the above-described polyester composition and then stretching and heat setting the film to control the crystallinity in the specific range. Further, it has been found that this stretched film is suitable as a packing material for foods and the like.
Namely, the first invention of the present invention is an aliphatic polyester composition comprising 10 to 60 parts by weight of at least one compound selected from (A) a compound represented by the general formula (1) 
(wherein, at least one of R1, R2 and R3 represents an acyl group having 6 to 18 carbon atoms, and remaining groups represent a hydrogen atom or an acetyl group.)
and (B) a compound which is a reaction product of a condensate of 1 to 10 glycerin molecules with a carboxylic acid having 6 to 18 carbon atoms, based on 100 parts by weight of an aliphatic polyester.
In this polyester composition, the aliphatic polyester is preferably a lactic acid-based polymer. As the lactic acid-based polymer, polylactic acid, lactic acid-other aliphatic hydroxycarboxylic acid copolymer, or a mixture thereof is preferable. It is preferable that the number of glycerin molecules of a glycerin condensate forming the compound (B) is from 2 to 10. Further, it is preferable that the compound (A) and the compound (B) are included in the composition, and the ratio by weight of (A):(B) is from 1:1 to 4:1.
The second invention is an aliphatic polyester stretched film having a crystallinity of 20 to 60% which is obtained by molding the above-described aliphatic polyester composition. The thickness of the stretched film is preferably from 5 to 1,000 xcexcm.
The third invention is a package which is obtained by packing a product to be packed using the above-described aliphatic polyester stretched film.
The aliphatic polyester composition of the present invention has excellent flexibility, and in addition, is suitable as a raw material of a stretched film and the like in which a plasticizer does not bleed out onto the surface. The aliphatic polyester stretched film of the present invention has excellent heat resistance and flexibility, and further, manifests no bleeding out of a plasticizer. Further, when the aliphatic polyester is polylactic acid, a lactic acid-other aliphatic hydroxycarboxylic acid copolymer comprising 40 mol % or more of a lactic acid unit, or an aliphatic polyester comprising a polyfunctional polysaccharides and 50 mol % or more of a lactic acid unit, and an aliphatic polyester comprising an aliphatic polyvalent carboxylic acid unit, aliphatic polyvalent alcohol unit and a lactic acid unit, the stretched film has degradability within the natural environment and does not accumulate as industrial waste or household waste even if discarded after use.
Therefore, the stretched film can be suitably used as a material in a wide range such as various packing films for foods, electronic products, medical products, medicines, cosmetics and the like, agricultural films, building and contracting films, adhesive tapes and the like. In particular, the stretched film is suitable as a packing material for foods. When product to be packed in the package of the present invention is a food, composting treatment, for example, or the like is possible without separating the packing material from waste of the product to be packed.
The present invention will be described in detail below. First, the aliphatic polyester composition of the present invention will be described. The aliphatic polyester composition of the present invention is produced by adding and mixing, as a plasticizer, at least one compound selected from the above-described compound (A) and compound (B) into an aliphatic polyester.
The aliphatic polyester used in the present invention is an aliphatic polyester comprising a lactic acid unit in the molecule. Specific examples thereof include (1) polylactic acid, and lactic acid-other aliphatic hydroxycarboxylic acid copolymers, (2) aliphatic polyesters comprising polyfunctional polysaccharides and a lactic acid unit, (3) aliphatic polyesters comprising an aliphatic polyvalent carboxylic acid unit, an aliphatic polyvalent alcohol unit and a lactic acid unit, and (4) mixtures thereof. Namely, examples thereof include the lactic acid-based polymers (1) to (4). Among them, polylactic acid, and lactic acid-other aliphatic hydroxycarboxylic acid copolymers are preferable when transparency, hydrolyzability and the like of the resulting stretched film are taken into consideration. Preferable still is polylactic acid.
Lactic acid includes a L-lactic acid and a D-lactic acid. When referred to simply as lactic acid in the present invention, both the L-lactic acid and D-lactic acid are indicated unless otherwise stated. The molecular weight of a polymer indicates the weight-average molecular weight unless otherwise stated. As the polylactic acid used in the present invention, there are listed poly (L-lactic acid) solely composed of L-lactic acid, poly (D-lactic acid) solely composed of D-lactic acid, poly (DL-lactic acid) comprising a L-lactic acid unit and a D-lactic acid unit in various proportions, and the like. As the hydroxycarboxylic acid of a lactic acid-other aliphatic hydroxycarboxylic acid copolymer, there are listed glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, 6-hydroxycaproic acid and the like.
As the method for producing polylactic acid used in the present invention, a method in which L-lactic acid, D-lactic acid or DL-lactic acid is directly dehydrated and poly-condensed, a method in which a lactide, cyclic dimer of such lactic acid is ring opening-polymerized, and the like are listed. The ring opening polymerization may also be conducted in the presence of a compound having a hydroxyl group such as higher alcohol, hydroxycarboxylic acid and the like. The compound may be produced by any method. As the method for producing a lactic acid-other aliphatic hydroxycarboxylic acid copolymer, a method in which the above-described lactic acid and the above-described aliphatic hydroxycarboxylic acid are dehydrated and polycondensed, a method in which a lactide, cyclic dimer of the above-described lactic acid, and a cyclic body of the above-described hydroxycarboxylic acid are ring opening-copolymerized, and the like are listed. The copolymer may be produced by any method. The amount of a lactic acid unit contained in a lactic acid-other aliphatic hydroxycarboxylic acid copolymer is preferably at least 40 mol %.
Examples of polyfunctional polysaccharides used for producing an aliphatic polyester comprising polyfunctional polysaccharides and a lactic acid unit include cellulose, cellulose acetate, cellulose nitrate, methyl cellulose, ethyl cellulose, celluloid, viscose rayon, regenerated cellulose, cellophane, cupra, cupro-ammonium rayon, cuprofan, bemberg, hemicellulose, starch, acropectin, dextrin, dextran, glycogen, pectin, chitin, chitosan, gum arabic, cyamoposis gum, locust bean gum, acacia gum and the like, and mixtures, and derivatives. Among them, cellulose acetate and ethyl cellulose are preferable.
As the method for producing an aliphatic polyester comprising polyfunctional polysaccharides and a lactic acid unit, a method in which the above-described polysaccharides are reacted with the above-described polylactic acid, lactic acid-other aliphatic hydroxycarboxylic acid copolymer and the like, a method in which the above-described polysaccharides are reacted with the above-described lactic acid, cyclic esters and the like, as well as other methods are listed. The aliphatic polyester may be produced by any method. It is preferable that the amount of a lactic acid unit contained in the aliphatic polyester is at least 50 mol %.
Examples of the aliphatic polyvalent carboxylic acid used for producing an aliphatic polyvalent carboxylic acid unit, an aliphatic polyvalent alcohol unit and a lactic acid unit include oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid and the like, and anhydrides thereof. These may be mixed with an acid anhydride. Examples of the aliphatic polyvalent alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, neopentyl glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol and the like.
As the method for producing an aliphatic polyester comprising an aliphatic polyvalent carboxylic acid unit, an aliphatic polyvalent alcohol unit and a lactic acid unit, a method in which the above-described aliphatic polyvalent carboxylic acid and the above-described aliphatic polyvalent alcohol are reacted with the above-described polylactic acid, lactic acid-other aliphatic hydroxycarboxylic acid copolymer and the like, a method in which the above-described aliphatic polyvalent carboxylic acid and the above-described aliphatic polyvalent alcohol are reacted with the above-described polylactic acid, cyclic esters and the like, as well as other methods are listed. The aliphatic polyester may be produced by any method. It is preferable that the amount of a lactic acid unit contained in the aliphatic polyester is at least 50 mol %.
The molecular weight of the aliphatic polyester exerts an influence on processability into a film, and strength and degradability of the obtained film. When the molecular weight is low, strength of the obtained film decreases and the film may be broken in use. Further, degradation speed increases. On the other hand, when the molecular weight is high, processability lowers and film molding becomes difficult. From such a standpoint, the molecular weight of the aliphatic polyester is in a range from about 10,000 to about 1,000,000. A further preferable range is from 100,000 to 300,000.
In the present invention, there is used, as a plasticizer for the aliphatic polyester, at least one compound selected from (A) a compound represented by the above-described general formula (1) and (B) a compound which is a reaction product of a condensate of 1 to 10 glycerin molecules with a carboxylic acid having 6 to 18 carbon atoms. The additional amount of the plasticizer exerts an influence on crystallinity, flexibility, heat resistance and the like of the resultant stretched film. When the additional amount is too high, the crystallinity and heat resistance lower. When the additional amount is too low, sufficient flexibility is not obtained. From such a standpoint, it is preferable that the additional amount of the plasticizer is from 10 to 60 parts by weight based on 100 parts by weight of the aliphatic polyester. Preferably still, the additional amount is from 15 to 50 parts by weight.
The compound (A) used in the present invention is a glycerin ester represented by the general formula (1). In general, the amount of an acetyl group in this compound is 2 mol or less on average per 1 mol of glycerin. The amount of an acyl group having 6 to 18 carbon atoms (hereinafter, referred to as a C6 to C18 acyl group) is 0.9 mol or more on average per 1 mol of glycerin. The total amount of the acetyl group and C6 to C18 acyl group is in the range from 2.7 to 3.0 mol on average per 1 mol of glycerin. Preferably, the total amount of the acetyl group and C6 to C18 acyl group is in the range from 2.9 to 3.0 mol on average per 1 mol of glycerin. From the standpoints of the resin plasticizing effect, non-bleeding property and the like, acyl groups having 8 to 18 carbon atoms are preferable among the C6 to C18 acyl groups, in this glycerin ester.
Preferable still is an ester represented by the general formula (1) in which at least one of R1, R2 and R3 represents an acyl group having 8 to 18 carbon atoms and remaining groups represent an acetyl group. As a particularly preferable compound (A), glycerin diacetomonocaprylate, glycerin diacetomonolaurate and glycerin diacetomonooleate are listed. The compound (A) may be used alone or in an admixture. As a typical commercially available product of the compound (A), Rikemal PL-004, PL-012, PL-014 [trade name, manufactured by Riken Vitamin K.K.] and the like are listed.
In the present invention, the compound (B) which is used as a plasticizer is usually a compound obtained by reacting 0.8 to 1.2 mol of a carboxylic acid having 6 to 18 carbon atoms with 1 mol of a condensate of 1 to 10 glycerin molecules. As a typical commercially available product thereof, Rikemal L-71-D, S-71-D, DL-100, A-3750 [trade name, manufactured by Riken Vitamin K.K.] and the like are listed. From the standpoints of the resin plasticizing effect, non-bleeding property and the like, an ester compound of a condensate of 2 to 10 glycerin molecules with a carboxylic acid having 8 to 18 carbon atoms is preferable. Preferable still is an ester of a condensate of 4 to 10 glycerin molecules with a carboxylic acid. As the particularly preferable specific compound, tetraglycerin caprylate, decaglycerin laurate and decaglycerin oleate are listed. The compound (B) may be used alone or in an admixture. As a typical commercially available product of the compound (B), Poem J-4081, J-6021, J-0021, J-0381 [trade name, manufactured by Riken Vitamin K.K.] and the like are listed.
In view of suppression of the bleeding of a plasticizer, it is preferable to use the compound (A) and the compound (B) together. In this case, it is preferable that the mixing ratio by weight of (A):(B) is in the range from 1:1 to 4:1. A further preferable mixing ratio by weight of (A):(B) is in the range from 2:1 to 3:1.
In the aliphatic polyester composition of the present invention, in addition to the main components, aliphatic polyester, compound (A) and compound (B), other additives such as an anti-blocking agent, lubricant, antistatic agent, anti-fogging agent, ultraviolet ray absorber, heat stabilizer, antioxidant, coloring inhibitor, filler, pigment, flame retardant and the like maybe added in the range wherein the object of the present invention can be accomplished.
As the anti-blocking agent, silica, calcium carbonate, titania, mica, talc and the like are listed. As the lubricant, hydrocarbons such as liquid paraffin, polyethylene wax and the like, fatty acids such as stearic acid and the like, oxyfatty acids, fatty amides, alkylene bisfatty amides, fatty acid lower alcohol esters, fatty acid polyvalent alcohol esters, fatty acid polyglycol esters, aliphatic alcohols, polyvalent alcohols, polyglycols, metal soaps such as calcium stearate and the like are listed.
As the antistatic agent, fatty acid salts, higher alcohol sulfuric acid esters, liquid fatty oil sulfuric acid ester salts, aliphatic amines and aliphatic amides sulfuric acid salts, aliphatic alcohol phosphoric acid ester salts, sulfonic acid salts of dibasic fatty acid esters, aliphatic amide sulfonic acid salts, alkylallylsulfonic acid salts, aliphatic amine salts, quaternary ammonium salts, alkylpyridium salts, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, polyoxyethylene sorbitan alkyl esters, imidazoline derivatives, higher alkylamines and the like are listed.
As the anti-fogging agent, glycerin fatty esters such as glycerin monostearate and the like, sorbitan fatty esters such as sorbitan monolaurate, sorbitan monooleate and the like, polyglycerin fatty esters, propylene glycol fatty esters and the like are listed. As the ultraviolet ray absorber, benzotriazoles such as 2-(2xe2x80x2-hydroxy-5xe2x80x2-methylphenyl)benzotriazole and the like, benzophenones such as 2-hydroxy-4-methoxybenzophenone and the like, salicylic acid derivatives such as p-tert-butylphenyl salicylate and the like, are listed.
As a heat stabilizer, antioxidant and coloring inhibitor, phenol-based compounds such as p-methoxyphenol and the like, phosphite-based compounds such as triphenylphosphite and the like, sulfur-based compounds such as 2-mercaptobenzimidazole and the like, amine-based compounds such as phenylnaphthyleneamine and the like, are listed. As filler, barium sulfate, titanium oxide, kaolin, carbon black and the like are listed. As a flame retardant, halogen-based compounds such as decabromodiphenyl ether and the like, antimony-based compounds such as antimony trioxide and the like, are listed.
Next, the aliphatic polyester stretched film of the present invention and an example of a method for producing the same will be described. As the method for adding and mixing a plasticizer into an aliphatic polyester, there can be adopted a method in which the aliphatic polyester and plasticizer, and other optional additives are mixed uniformly using a high speed stirrer, low speed stirrer or the like, then the mixture is melted and kneaded using a single screw or multi-screw extruder having sufficient kneading ability, as well as other methods. The resin composition of the present invention is preferably in the form of a pellet, rod, powder and the like.
The resin composition obtained as described above is molded into a film by a melt extrusion method using an extruder equipped with a T die. The resulting film is stretched along the machine direction (hereinafter, referred to as longitudinal direction) by a roll stretching method, then, stretched along a direction vertical to the machine direction (hereinafter, referred to as transverse direction) by a tenter stretching method. After stretching, the film is heat-treated under tension to obtain an aliphatic polyester stretched film. This film can be produced also by a melt extrusion using an extruder equipped with a circular die, namely, a tubular molding method.
The melt extrusion temperature of the above-described aliphatic polyerster composition is in a range preferably from 100 to 280xc2x0 C., and more preferably from 130 to 250xc2x0 C. When the molding temperature is lower, molding stability cannot be obtained easily and an excess load tends to occur. On the other hand, when the molding temperature is higher, the aliphatic polyester may be degraded causing an undesirable decrease in molecular weight, a decrease in strength, coloring and the like.
The aliphatic polyester stretched film of the present invention is obtained by stretching along at least one direction of the longitudinal direction and transverse direction by 1.3 to 5 times, and preferably 1.5 to 5 times. Biaxial stretching along the longitudinal direction and transverse direction is preferable. When stretching magnification is less than 1.3 times, crystallization causing stability over time in dynamic physical property and dimension accuracy does not proceed easily. On the other hand, when stretching magnification is over 5 times, flexibility of a film decreases leading to an undesirable break in the film and the like in stretching.
The stretching temperature is preferably in a range from the glass transition temperature (Tg) of an aliphatic polyester to (Tg+50)xc2x0C. More preferably, it is in the range from Tg to (Tg+30)xc2x0C. When the stretching temperature is less than Tg, stretching is difficult, and when over (Tg+50)xc2x0C., uniform stretching is undesirably difficult. For improving heat resistance and dimension stability, heat setting is conducted under tension at a temperature of (Tg+10)xc2x0C. or more and less than the melting temperature after stretching. In this operation, the crystallinity of a film can be controlled by changing the stretching and heat setting conditions.
By conducting stretching and heat setting under the above-described conditions, a stretched film is obtained having a crystallinity of 20 to 60%. The preferable crystallinity is from 20 to 50%. For example, 20 parts by weight of glycerin diacetomonolaurate which is one of compound (A) is added to 100 parts by weight of an aliphatic polyester, the mixture is processed through a T die to form a film, then, the film is stretched along the longitudinal direction by 2.5 times and along the transverse direction by 2.5 times (hereinafter, abbreviated as 2.5xc3x972.5) at 50xc2x0 C. Then, the film is subjected to heat setting at 140xc2x0 C. under tension to obtain a stretched film having a crystallinity of about 35%. Usually, in the case of an inflation molding method, a tubular (seamless) product is formed in the form of a wound product. The thickness of the aliphatic polyester stretched film of the present invention can be appropriately changed depending on use, and usually is in the range from 5 to 1000 xcexcm.
Herein, the package of the present invention will be described. The package of the present invention is formed by packing a product to be packed using the above-described aliphatic polyester stretched film. The above-described aliphatic polyester stretched film may be cut in a given dimension and used as a cut sheet, or the above-described aliphatic polyester stretched film may be formed into a bag. In the case of a bag, it is preferable that a product to be packed is filled in a bag, then, the opening is sealed. As the sealing method, there are listed a heat seal method, high frequency seal method, adhesive tape fixing method, binding method using a cord, aluminum wire, copper wire and the like, as well as other methods. In addition, one surface at the opening part is made longer than the other surface, and the leading point is folded for sealing. When the product to be packed is a product to be discarded, a heat seal method, high frequency seal method, and fixing method using a degradable adhesive tape are preferable.
Usually, in the case of a cut sheet, a film in the form of a wound product is cut into a length of about 5 to 100 cm for use. In the case of a bag, a bag having a width of 5 to 100 cm and a depth of 5 to 100 cm is formed to be used. The filling amount of product to be packed is about 0.1 g to 10 kg.
As the method for forming an adhesive layer, there is, for example, a method in which application liquid containing an acrylic resin such as a copolymer obtained by copolymerizing an alkyl acrylate such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like with other vinyl monomers is applied on a film and dried. The application liquid may be an organic solvent solution of the above-described copolymer or an aqueous emulsion.
The product to be packed is not particularly restricted. Usually, there are listed foods, pharmaceuticals, cosmetics, fertilizers, electronic and electric products and parts thereof, paper products, and wastes thereof and the like. Preferably, there are listed foods such as vegetables, fruits, fishery products, meats, cereals, dry goods, breads, dairy products, noodles, confections, edible wild plants, seasonings and the like, and waste thereof, and the like.
In the case of a bag, specific examples thereof include a food bag, shopping bag, trash bag, compost bag, soil bag and the like. In the case of a cut sheet, specific examples thereof include a food wrapping film, cosmetic wrapping film, pharmaceutical wrapping film, surgical application wrapping film, agricultural chemical wrapping film, wrapping film for electronic and electric products such as video, audio, and the like.
In addition, the film of the present invention can be used as an agricultural film for gardening plants and the like, a substrate film for a adhesive tape, a water-proof sheet and the like.
In the aliphatic polyester stretched film of the present invention, layers having functions such as antistatic property, anti-fogging property, adhesiveness, gas-barrier property, tight adhesion, easy adhesion and the like can be formed on the surface thereof, if necessary. As the method for forming these layers, an application method, laminate method and the like are listed. In the application method, for example, coating liquid containing an antistatic agent can be applied on one surface or both surfaces of a film and dried to form an antistatic layer. As the method for applying coating liquid, known methods can be used. That is, there can be used a spray coating method, air knife method, reverse coating method, kiss coating method, gravure coating method, meyer bar method, roll brush method and the like.
As the method for forming an adhesive layer, there is, for example, a method in which application liquid containing an acrylic resin such as a copolymer obtained by copolymerizing an alkyl acryalte such as ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and the like with other vinyl monomers is applied on a film and dried. The application liquid may be an organic solvent solution of the above-described copolymer or an aqueous emulsion.
Further, in the aliphatic polyester stretched film of the present invention, layers having functions such as antistatic property, anti-fogging property, adhesiveness, gas-barrier property, tight adhesion, easy adhesion and the like can be formed by laminating other resin film, if necessary. As the lamination method, known methods such as an extrusion lamination method, dry lamination method and the like can be used.